With diversity of mobile platforms iOS, Android, Blackberry, Symbian, Windows Phone 7, Meego, WebOS, Bada and many more, developers all around the world face incredible challenge to design and build mobile apps twhat run on all this platforms.
When you build an application for a mobile device you usually build it using the SDK specifically for that platform. This gives you a completely native look and feel, as well as full access to features specific to that device or operating system. Sometimes, however, you don't need full device access. Sometimes you might want code at a very high level using just web standards and be able to run the application on multiple OSes. This is similar to coding a mobile website, except that as an local application your app can launch faster, work offline, and have access to local resources.
Phonegap only requires you to setup the right kind of development environment for the platform and you are ready. Obviously, when we are talking about native applications, the SDKs and other platforms requirements have to be met. Once, you write your first mobile application, you will also need the simulators to test it.
Features and Limitations of Phonegap:
The Phonegap website hosts a list of native features that it supports for each platform. What does this mean? Well, an HTML/JS based framework might be considered weak in terms of its capabilities to interact with hardware and native tools and APIs. Yes, Phonegap might not be best solution for every project but you can always have a glance at the supported features and convince yourself whether it suits your requirements.
The 1.0 release of PhoneGap also features a new unifying bridge interface that makes adding platforms and platform extensions easier. Additionally, the plug-in development process has been simplified.
http://www.youtube.com/watch?v=E0UV5i5jY50&feature=youtu.be for more info
For more info